High-frequency, low-intensity pulsed electric field and N-acetylcysteine synergistically protect SH-SY5Y cells against hydrogen peroxide-induced cell damage in vitro

ABSTRACT Oxidative stress plays an important role in the progression of neurodegenerative diseases (NDDs), and N-acetylcysteine (NAC) has gained attention as a potential agent due to its antioxidant capabilities. This study investigated the synergistic neuroprotective effects of combining NAC with non-contact high-frequency low-intensity pulsed electric field (H-LIPEF) stimulation on SH-SY5Y human neuronal cells subjected to hydrogen peroxide (H2O2)-induced oxidative damage. It was found that after SH-SY5Y cells were pretreated with NAC and exposed to H-LIPEF stimulation, the oxidative stress of cells was reduced in the subsequent treatment with H2O2. The results showed that the combined NAC and H-LIPEF treatment significantly improved cell viability and better preserved cellular morphology compared to either treatment alone. Additionally, this combination treatment more effectively reduced mitochondrial apoptosis. Mechanistic analyses revealed that the combination substantially decreased levels of superoxide and intracellular H2O2, which was associated with enhanced activation of the p-Akt/Nrf2/SOD2 signaling pathway. Furthermore, the treatment reduced the accumulation of 8-oxo-dG accumulation and elevated MTH1 expression, indicating a protective effect against oxidative DNA damage. These results suggest that H-LIPEF enhances the neuroprotective efficacy of low-dose NAC, highlighting the potential of this combination approach as a new therapeutic strategy for the treatment of NDDs. Competing Interest Statement The authors have declared no competing interest. Footnotes tsyr8924503{at}phys.ntu.edu.tw (F.T.H.); yykuo{at}phys.ntu.edu.tw (Y.Y.K.); cychao{at}phys.ntu.edu.tw (C.Y.C.) Abbreviations - NDDs - Neurodegenerative diseases - AD - Alzheimer’s disease - PD - Parkinson’s disease - ROS - reactive oxygen species - NAC - N-acetylcysteine - BBB - blood-brain barrier - Nrf2 - nuclear factor erythroid 2-related factor 2 - SOD2 - superoxide dismutase type 2 - LIPEF - low-intensity pulsed electric field - H-LIPEF - high-frequency low-intensity pulsed electric field - ROCK - rho-associated protein kinase - ERK - extracellular signal-regulated kinase - MTH1 - MutT homolog 1 - FBS - fetal bovine serum - MTT - 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide - SDS - sodium dodecyl sulfate - PBS - phosphate-buffered saline - PVDF - polyvinylidene fluoride - PARP - poly (ADP-ribose) polymerase - p-Akt - phosphorylated Akt - GAPDH - glyceraldehyde 3-phosphate dehydrogenase - DHE - dihydroethidium - DiOC6(3) - 3,3’-dihexyloxacarbocyanine iodide - 8-oxo-dG - 8-oxo-2’-deoxyguanosine triphosphate - DAPI - 4’,6-diamidino-2-phenylindole - ANOVA - one-way analysis of variance - MMP - mitochondrial membrane potential